Vasoocclusion devices are surgical implements that are placed within vessels, typically via a catheter to block the flow of blood through the vessel. One type of vasoocclusive device is a helical wire coil that has windings that are dimensioned to engage the walls of the vessels. Fibers are laid crosswise through the windings to provide a substrate for embolization within the vessel. Coils of such structure are available commercially from Cook, Inc.
U.S. Pat. No. 4,994,069 describes a vasoocclusive coil that assumes a linear helical configuration when stretched and a folded convoluted configuration when relaxed. The stretched condition is used in placing the coil at the desired site and the coil assumes its relaxed configuration--which is better suited to occlude the vessel--once the device is so placed.
A principal object of the present invention is to provide a helical vasoocclusion coil to which fibrous elements are attached in a manner that ensures they will not be dislodged from the coil and enhances the ability of the coil to facilitate embolization.